Energy management system for a hybrid-electric vehicle

ABSTRACT

A system for optimizing electrical power management in a vehicle. The system includes a HVAC device and a thermal storage device, both configured to provide heating and cooling to an occupant compartment of the vehicle. The system further includes a controller connected to an electrical storage device and an electrical generating device. The controller receives electrical power generated by the electrical generating device and directs the electrical power to satisfy the vehicle&#39;s power requirements and/or stores the electrical power in at least one of the electrical storage device and the thermal storage device. Furthermore, the controller directs at least one of the HVAC device and the thermal storage device to provide heating and cooling to the occupant compartment of the vehicle, depending on the available storage of the thermal storage unit or occupant compartment demands.

BACKGROUND

1. Field of the Invention

The present invention generally relates to energy management systems ofa vehicle, in more particularly to energy management systems of ahybrid-electric vehicle.

2. Description of the Known Technology

A hybrid-electric vehicle uses an electric motor in conjunction with aconventional internal combustion engine to create torque to drive itswheels. When the driver of the hybrid-electric vehicle applies thebrakes, the hybrid-electric vehicle reverses the function of theelectric motor, thus, turning the electric motor into an electricgenerator. As the hybrid-electric vehicle approaches the stop, thewheels of the hybrid-electric vehicle, in conjunction with the electricmotor acting as an electric generator, generate a pulse of electricalpower. This pulse of electrical power is stored in an energy storagedevice such as a capacitor or battery and later used to drive the wheelsand/or power the vehicle accessories, such as a heating, ventilation andair conditioning (“HVAC”) system. However, because of the nature of thepulse, when storing the electrical power, some of the electrical poweris lost due to parasitic losses.

The electric motor, acting as an electric generator, is not the onlysource of electrical power in a hybrid-electric vehicle. For example, analternator and heat capture devices, such as thermoelectric devicesplaced on the exhaust of the hybrid-electric vehicle, may be utilized togenerate electrical power. This electrical power may be stored in anenergy storage device. Similar to the electrical power generated by theelectric motor, some of the generated electrical power is lost due toparasitic losses.

When the hybrid-electric vehicle is at a stop, it is common for thehybrid-electric vehicle to shut down its internal combustion engine.However, when the HVAC system of the hybrid-electric vehicle is inoperation, the hybrid-electric vehicle may have to drain the energystorage device and/or keep the internal combustion engine operating inorder to keep the HVAC system running. These demands will decrease fueleconomy.

Therefore, it is desire to provide a more efficient system for providingheating and cooling to the occupant compartment of the hybrid-electricvehicle while maximizing the storage of the pulse of electrical powergenerated during braking and by the other electrical power generated bythe hybrid-electric vehicle.

BRIEF SUMMARY

In overcoming the drawbacks and limitations of the known technologies, asystem method for managing electrical power generated by a vehicle isdisclosed. The system includes a HVAC device and a thermal storagedevice both being configured to provide heating and cooling to anoccupant compartment of the vehicle. The system further includes acontroller connected to an electrical storage device and an electricalgenerating device. The electrical generating device may be severaldevices, such as an alternator, a regenerative braking generator and awaste recovery power generator. The controller will receive electricalpower generated by the electrical generating device and store theelectrical power in at least one of the electrical storage device andthe thermal storage device. Furthermore, the controller will direct atleast one above the HVAC device and the thermal storage device toprovide heating and cooling to the occupant compartment of the vehicle.

As to the method, the method includes the steps of receiving electricalpower, monitoring the available storage of the electrical and thermalstorage devices and storing the electrical power received in at leastone of the electrical storage device and the thermal storage device.Furthermore, the method may include the steps of storing the electricalpower in the electrical storage device when the thermal storage deviceis at a maximum capacity and storing electrical power in the thermalstorage device when the thermal storage device is below a maximumcapacity.

The method may further include steps for providing heating and coolingto the occupant compartment of the vehicle. This includes monitoring thethermal requirements of the occupant compartment and providing heatingand cooling to the occupant compartment from at least one of the thermalstorage device and the HVAC device based upon the thermal requirementsof the occupant compartment. If the thermal requirements of the occupantcompartment can be met solely by the thermal storage device, the thermalstorage device will provide the heating and cooling. However, if thethermal requirements of the occupant compartment will not be satisfiedby the thermal storage device, the HVAC device may supplement thethermal storage device or solely provide the heating and cooling.

These and other advantages, features and embodiments of the inventionwill become apparent from the drawings, detailed description and claimswhich follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an energy management system for a vehicleembodying the principles of the present invention; and

FIG. 2 is a block diagram of second embodiment of an energy managementsystem for a vehicle according to the principles of the presentinvention.

DETAILED DESCRIPTION

Referring to FIG. 1, the various components of an energy managementsystem 10 for a vehicle according to one embodiment of the presentinvention are shown. The energy management system 10 includes acontroller 12 connected to an alternator 14, a regenerative brakingsystem generator 16, and a waste heat recovery system 18. The controller12 may be one controller or multiple controllers in communication witheach other.

The alternator 14 is preferably a belt driven alternator, driven by anengine (not shown) of the vehicle and has clutches that selectivelycreate electrical power. The regenerative brake system generator 16 ispreferably a regenerative braking system commonly used onhybrid-electric vehicles, which generate electrical power while thehybrid-electric vehicle is braking. The waste heat recovery generatorsystem 18 is preferably a system for capturing heat created by thevehicle during operation. The waste heat recovery generator system 18may be one or more thermoelectric modules located near areas of thevehicle which create heat, such as the exhaust and engine of thevehicle. Electrical power generated by the alternator 14, theregenerative braking system generator 16, and the waste heat recoverysystem 18 is directed to the controller 12.

The controller 12 is also connected to an electrical storage device 20and stores electrical power generated by the alternator 14, theregenerative braking system generator 16, and the waste heat recoverysystem 18. The electrical storage device 20 is preferably one or morecapacitors or batteries, but may be any device suitable for storingelectrical power.

Connected to the controller 12 is a HVAC device 24. The HVAC device 24is preferably an electrical HVAC device but may be a conventional beltdriven device or any vehicle heating and cooling system that is nowknown or later developed. If a conventional belt driven HVAC system isutilized, a system of clutches may be implemented to selectively placethe HVAC unit in an operating mode. One or more ducts 29 are coupled tothe HVAC device 24 and direct conditioned, heated or cooled air from theHVAC device 24 to the occupant compartment 26.

A thermal storage device 22 is coupled to the HVAC unit 24. In certainsituations described below, the HVAC unit 24 converts the electricalpower directed to the HVAC unit 24 from the controller 12 into thermalpower and stores this thermal power in the thermal storage device 22.Typically, one or more thermoelectric devices are utilized to convertthe electrical power into thermal power but any suitable electricalpower to thermal power conversion device may be used. In order to storethe thermal power, the thermal storage device 22 may contain both a highand low temperature phase change material, such as wax (a hightemperature phase change material) and water (a low temperature phasechange material).

The energy management system 10 further includes an electrical storagelevel sensor 32 and a thermal storage temperature sensor 34 fordetermining the available amount of storage available for electrical andthermal power in the electrical storage device 20 and the thermalstorage device 22, respectively. An occupant compartment temperaturesensor 36 is connected to controller 12, such that the temperature ofthe occupant compartment can be monitored by the controller 12.

Last, the energy management system 10 further includes vehicleaccessories 37 connected to the controller 12. The vehicle accessories37 may include fuel injectors, interior and exterior lighting, vehicleinformation, entertainment and navigation systems or any electricalpowered device found in the vehicle. The controller 12 direct electricalpower to the accessories 37 as needed.

When in operation, the controller 12 will receive electrical powergenerated from at least one source, such as the alternator 14, theregenerative brake system generator 16 or the waste heat recovery system18. The controller will monitor the available amount of storageremaining for electrical and thermal power storage by monitoring theoutput of the electrical storage level sensor 32 and the thermal storagetemperature sensor 34, respectively. Based upon the remaining storageavailable in the thermal storage device 22, the controller 12 willdirect the electrical power to either the electrical storage device 20or the HVAC unit 24. The HVAC unit 24 will then function to convert theelectrical power to thermal power and store the thermal power in thethermal storage device 22 for later use.

If the thermal storage device 22 has inadequate suitable storage forstoring the thermal power, the electrical power will be directed to theelectrical storage device 20. Alternatively, the controller 12 candirect a portion of the electrical power to be stored in the thermalstorage device 22 and the rest of the electrical power to the electricalstorage device 20. It is preferred to first store the electrical powerin the thermal storage device 22, rather than the electrical storagedevice 20, because it is more efficient to store the thermal power inthe thermal storage device 22.

The controller 12 will also monitor the temperature of the occupantcompartment 26 via the occupant compartment temperature sensor 36 anddirect the HVAC device 24 to provide heating or cooling to the occupantcompartment 26. The HVAC may provide all or part of the heating andcooling to the occupant compartment 26 by using the thermal power storedin the thermal storage device 22 or may generate the required thermalpower on its own. Also, the HVAC device 24 may supplement the heatingand cooling it provides to the occupant compartment 26 with the thermalpower stored in the thermal storage unit 22.

By having the thermal storage device 22 provide all or part of theheating and cooling to the occupant compartment 26, the vehicle may beable to not require HVAC device 24 to generate the necessary heating andcooling for extended periods of time. By minimizing the use of the HVACdevice 24 for generating the heating and cooling, the vehicle will beable to achieve greater fuel efficiency.

Referring to FIG. 2, another embodiment of an energy management system10′is shown therein, wherein similar reference numerals used in FIG. 2denote identical components as in the embodiment of FIG. 1. The energymanagement system 10′differs from the one shown in FIG. 1 in that thethermal storage device 22 will receive electrical power directly fromthe controller 12, convert the electrical power to thermal power andstore the thermal power. Furthermore, the HVAC device 24 and the thermalstorage device 22 direct heated or cooled air to the occupantcompartment 26 via separate ducts 28, 30, respectively.

The controller 12 is configured to determine if the occupant compartment30 can be sufficiently heated or cooled by the thermal storage device 22through the duct 28. If the occupant compartment 26 can be adequatelyheated or cooled by the thermal storage device 22, the controller 12will direct the thermal storage device to provide the heating or coolingto the occupant compartment 26, while leaving the HVAC in an “off”state.However, if the controller 12 determines that the thermal storage device22 is unable to provide adequate heating and cooling to the occupantcompartment 26, the controller may direct the HVAC device 24 and thethermal storage device 22 to both provide adequate heating and coolingto the occupant compartment 26. Alternatively, if the thermal storagedevice 22 is unable to provide adequate heating and cooling to theoccupant compartment 26, the controller may direct HVAC device 24 tosolely provide heating and cooling to the occupant compartment 26.

The foregoing description of the embodiment of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the preciseembodiment disclosed. Numerous modifications or variations are possiblein light of the above teaching. The embodiment discussed was chosen anddescribed to provide the best illustration of the principles of theinvention in its practical application to thereby enable one of ordinaryskill in the art to utilize the invention in various embodiments andwith various modifications as are suited to the particulate usecontemplated. All such modifications and variations are within the scopeof the invention as determined by the appended claims when interpretedin accordance with the breadth to which they are fairly, legally, andequitably entitled.

The invention claimed is:
 1. An energy management system for a vehiclecomprising: a heating, ventilation and air conditioning (“HVAC”) deviceto provide heating and cooling to an occupant compartment of thevehicle; a thermal storage device configured to provide heating andcooling to the occupant compartment of the vehicle; an electricalstorage device; a controller configured to receive electrical power froman electrical generating device, the controller connected to theelectrical storage device and the HVAC device and configured to storethe electrical power in at least one selected from the group consistingof the electrical storage device and the thermal storage device; and athermal storage temperature sensor connected to the controller thatmonitors available storage of the thermal storage device; wherein thecontroller is further configured to determine whether to direct theelectrical power to the electrical storage device or the thermal storagedevice based on the available storage of the thermal storage device and,based on that determination, to direct the electrical power to eitherthe electrical storage device or the thermal storage device.
 2. Thesystem of claim 1, wherein the electrical generating device is at leastone selected from the group of an alternator, a regenerative brakinggenerator and a waste recovery power generator.
 3. The system of claim1, wherein the controller directs at least one of the HVAC device andthe thermal storage device to provide heating and cooling to theoccupant compartment of the vehicle.
 4. The system of claim 3, whereinthe thermal storage device provides heating and cooling to the occupantcompartment of the vehicle via a duct coupled to the HVAC device.
 5. Thesystem of claim 1, further comprising an occupant compartmenttemperature sensor connected to the controller for monitoring at least aportion of the occupant compartment of the vehicle.
 6. The system ofclaim 1, further comprising an electrical storage level sensor connectedto the controller for monitoring the available storage of the electricalstorage device.
 7. The system of claim 1, wherein the electrical storagedevice is configured to store the electrical power when the thermalstorage device has inadequate available storage.
 8. The system of claim1, wherein the electrical storage device is configured to store theelectrical power when the occupant compartment thermal needs have beenmet.
 9. The system of claim 1, wherein the thermal storage device isconfigured to receive the electrical power when the thermal storagedevice has adequate available storage.
 10. The system of claim 1,wherein the thermal storage device is configured to receive a firstportion of electrical power, and wherein the electrical storage deviceis configured to receive a second portion of electrical power after thefirst portion is received by the thermal storage device.
 11. The systemof claim 1, wherein the controller is configured to monitor the thermalrequirements of the occupant compartment and direct heating and coolingto be provided to the occupant compartment from at least one of thethermal storage device and the HVAC device based upon the thermalrequirements of the occupant compartment.
 12. The system of claim 1,wherein the thermal storage device is configured to provide heating andcooling to the occupant compartment when the thermal power stored in thethermal storage device is at least equal to the thermal requirements ofthe occupant compartment.
 13. The system of claim 1, wherein the HVACdevice is configured to provide heating and cooling to the occupantcompartment when thermal power stored in the thermal storage device isless than the thermal requirements of the occupant compartment.
 14. Thesystem of claim 13, wherein heating and cooling to the occupantcompartment is provided solely from the HVAC device.
 15. The system ofclaim 13, wherein heating and cooling to the occupant compartment isprovided from both from the HVAC device and the thermal storage device.16. The system of claim 1, wherein the controller is configured todirect the electrical power to the thermal storage device by directingthe electrical power to the HVAC device for conversion to thermal powerand storing the thermal power in the thermal storage device.
 17. Thesystem of claim 1, wherein the controller directs a portion of theelectrical power to the thermal storage device and the rest of theelectrical power to the electrical storage device.
 18. The system ofclaim 1; wherein the controller is configured to direct the electricalpower to the thermal storage device while the thermal storage device hasremaining available storage and to direct the electrical power to theelectrical storage device when the thermal storage device has inadequatesuitable storage.
 19. The system of claim 1, wherein the thermal storagedevice receives electrical power directly from the controller andconverts the electrical power to thermal power for storage in thethermal storage device.
 20. The system of claim 1, wherein thecontroller is configured to direct the electrical power to the thermalstorage device by converting the electrical power to thermal power andstoring the thermal power in the thermal storage device.
 21. The systemof claim 1, wherein the HVAC device receives electrical power directlyfrom the controller and converts the electrical power to thermal powerfor storage in the thermal storage device.
 22. The system of claim 1,wherein the electrical power is not stored in an electrical storagedevice when it is determined that the thermal storage device hasadequate available storage.